Officials in Boston, Massachusetts, have released surveillance video of a Boston police officer and FBI agent fatally shooting Usaama Rahim last week. Authorities say they had been monitoring Rahim as part of a terrorism probe when they overheard him talking about beheading an officer. They say he lunged at officers with a knife. Boston Police Commissioner William Evans said the video supports that account.

William Evans: “You know, there’s questions asked about why didn’t the officers use any other force. You know, this guy had a malicious intent, and our officers were really faced with that, both the FBI and the Boston. And the video will speak for itself.”

But Rahim’s family has disputed the police version, saying the video shows Rahim was not the initial aggressor. The grainy video makes it difficult to tell what happened or even whether Rahim has a knife.